Control system, disconnection detection method, and non-transitory computer-readable medium

ABSTRACT

A control system includes: a semiconductor chip, having built therein a processing part, an A/D converter and a pull device circuit; a wiring part, having one end connected to a terminal connected to the A/D converter; and a sensor, connected to the other end of the wiring part and inputting a sensor signal in analog form via the wiring part. The pull device circuit includes a switching element, and has one end connected to ground or a power supply voltage and the other end connected between the A/D converter and the terminal. The processing part includes: a switch control part, controlling the switching element to be in an on or off state; a sensor information generator, generating sensor information based on the sensor signal; and a disconnection detector, detecting disconnection of the wiring part based on output of the A/D converter when the switching element is in the on state.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims the priority benefit of Japan Application No.2021-147004, filed on Sep. 9, 2021. The entirety of the above-mentionedpatent application is hereby incorporated by reference herein and made apart of this specification.

BACKGROUND Technical Field

The disclosure relates to a control system, a disconnection detectionmethod, and a disconnection detection program.

Related Art

An electronic control device is known including: a ground terminal forgrounding a shielded wire used to output a drive signal to an inductiveload via a drain wire; a series circuit of a resistor element and aswitching element connected between a power supply and the groundterminal; and a disconnection detector detecting disconnection of thedrain wire by switching the switching element on and off.

-   [Patent Document 1] Japanese Patent Laid-open No. 2020-139787

In a configuration in which an analog sensor signal is input to aterminal of a semiconductor chip via a wiring part, it is useful to beable to realize a mechanism capable of detecting disconnection of thewiring part at low cost without adding a new component.

SUMMARY

One aspect of the disclosure provides a control system. The controlsystem includes: a semiconductor chip, having built therein a processingpart, an A/D converter and a pull device circuit; a wiring part, havingone end connected to a terminal connected to the A/D converter; and asensor, connected to the other end of the wiring part and inputting asensor signal in analog form to the terminal via the wiring part. Thepull device circuit includes a switching element, and has one endconnected to ground or a power supply voltage and the other endconnected between the A/D converter and the terminal. The processingpart includes: a switch control part, controlling the switching elementto be in an on or off state; a sensor information generator, generatingsensor information based on the sensor signal; and a disconnectiondetector, detecting disconnection of the wiring part based on output ofthe A/D converter when the switching element is in the on state.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 schematically illustrates an embodiment of a hydraulic pressuregeneration device.

FIG. 2 is a configuration diagram schematically illustrating anembodiment of a motor control device.

FIG. 3 is a schematic diagram illustrating an internal configuration ofeach of a microcomputer and a temperature sensor.

FIG. 4 is an explanatory diagram of an output characteristic of atemperature sensor.

FIG. 5 is an explanatory diagram of disconnection in a wiring part.

FIG. 6 is an explanatory diagram of an output characteristic of an A/Dconverter when a pull-up circuit is turned on in a normal mode.

FIG. 7 is an explanatory diagram of an output characteristic of an A/Dconverter when a pull-up circuit is turned on in a case wheredisconnection has occurred in a wiring part.

FIG. 8 is an explanatory diagram of a ground fault of a temperaturesensor.

FIG. 9 is a timing chart in a case where disconnection detectionprocessing by a disconnection detector is performed duringinitialization processing of a microcomputer.

FIG. 10 is a timing chart of a power fault-related failure determinationmethod by a sensor failure detector.

FIG. 11 is a timing chart of a ground fault-related failuredetermination method by a sensor failure detector.

FIG. 12 is a timing chart in a case where disconnection detectionprocessing by a disconnection detector is performed in a sleep mode of amicrocomputer.

DESCRIPTION OF THE EMBODIMENTS

In the disclosure, in a configuration in which an analog sensor signalis input to a terminal of a semiconductor chip via a wiring part,disconnection of the wiring part is detected without adding a newcomponent.

According to the disclosure, in the configuration in which the analogsensor signal is input to the terminal of the semiconductor chip via thewiring part, it is possible to detect the disconnection of the wiringpart without adding a new component (by using a pull device circuitbuilt in the semiconductor chip).

Hereinafter, embodiments of the disclosure are described with referenceto the drawings.

FIG. 1 schematically illustrates an embodiment of a hydraulic pressuregeneration device 1.

The hydraulic pressure generation device 1 is a device that generateshydraulic pressure, and is preferably mounted on a vehicle. As shown inFIG. 1 , the hydraulic pressure generation device 1 includes a motordrive system 2 and a hydraulic pump 3.

The motor drive system 2 includes a motor control device 10 and a motor12.

The motor control device 10 controls the hydraulic pump 3 by controllingthe motor 12. The motor control device 10 is a processing deviceincluding a microcomputer 110 or the like. The motor control device 10has a hardware configuration that is arbitrary and can be the same asthat of an in-vehicle electronic control unit (ECU).

In the motor 12, an output shaft 12 a functions as a drive shaft of thehydraulic pump 3. The motor 12 is a three-phase brushless motor.However, the number of phases is not limited thereto, and the detailedconfiguration is arbitrary. The motor 12 may be connected to thehydraulic pump 3 directly or via another mechanism (not shown) or thelike.

The hydraulic pump 3 is an electric pump. When driven, the hydraulicpump 3 sucks oil in a tank 31 and discharges the same to a supply path32.

In this way, the hydraulic pressure generation device 1 of the presentembodiment generates hydraulic pressure by driving the hydraulic pump 3via the motor drive system 2. The hydraulic pressure generated by thehydraulic pump 3 (that is, the oil discharged from the hydraulic pump 3)can be used in driving an actuator, cooling a heating component ofvarious in-vehicle electronic devices, or lubricating a movable part.

FIG. 2 is a configuration diagram schematically illustrating anembodiment of the motor control device 10. FIG. 2 also shows a host ECU4 as a related configuration. FIG. 3 is a schematic diagram illustratingan internal configuration of each of the microcomputer 110 and atemperature sensor 122.

The host ECU 4 is an example of a control device of a higher order thanthe motor control device 10, and gives various commands to the motorcontrol device 10.

The motor control device 10 includes the microcomputer 110 and a drivedevice 120 as shown in FIG. 2 .

The microcomputer 110 controls the motor 12 via the drive device 120 inresponse to the various commands from the host ECU 4. The microcomputer110 monitors a temperature of the drive device 120 based on sensorinformation (described later) from the temperature sensor 122 of thedrive device 120.

The microcomputer 110 is in the form of a semiconductor chip, andincludes a processing part 111, an A/D converter 112, a pull-up circuit113, and a pull-down circuit 114 as shown in FIG. 3 .

The processing part 111 includes a central processing unit (CPU), astorage and the like, and performs various arithmetic processings.

The A/D converter 112 converts an analog signal input thereto into adigital signal and outputs the same. In the present embodiment, anelectric signal is input to the A/D converter 112 from the temperaturesensor 122 of the drive device 120. The A/D converter 112 inputs theoutput in the form of a digital signal to the processing part 111.

The pull-up circuit 113 has one end connected to a power supply voltageVcc (for example, 5 V) and the other end connected to an input line 1121to the A/D converter 112. The input line 1121 is an internal wire of themicrocomputer 110, and has one end connected to a terminal Tm1 of themicrocomputer 110 and the other end connected to the A/D converter 112.

The pull-up circuit 113 includes a switching element SW1 and a resistorR1. The switching element SW1 is in the form of, for example, atransistor (for example, bipolar transistor). The resistor R1 is a fixedresistor and may have a resistance value in the range of, for example,25 kΩ to 127 kΩ.

The pull-up circuit 113 is able to turn on/off its own function byturning on/off the switching element SW1. In the following, turningon/off the pull-up circuit 113 means turning on/off a function of thepull-up circuit 113 by turning on/off the switching element SW1.

The pull-down circuit 114 has one end connected to ground and the otherend connected to the input line 1121 to the A/D converter 112. Thepull-down circuit 114 includes a switching element SW2 and a resistorR2. The switching element SW2 is in the form of, for example, atransistor (for example, bipolar transistor). The resistor R2 is a fixedresistor and may have a resistance value in the range of, for example,25 kΩ to 127 kΩ.

The pull-down circuit 114 is able to turn on/off its own function byturning on/off the switching element SW2. In the following, turningon/off the pull-down circuit 114 means turning on/off a function of thepull-down circuit 114 by turning on/off the switching element SW2.

The drive device 120 is in the form of, for example, a control board,and has various electronic components mounted thereon. The drive device120 includes a drive circuit 121 and the temperature sensor 122.

The drive circuit 121 is in the form including, for example, an inverterand a driver, and controls a current flowing through the motor 12 inresponse to a drive signal from the microcomputer 110.

The temperature sensor 122 is in the form of, for example, a thermistor,and generates an electric signal (analog signal) corresponding to atemperature at a position where the temperature sensor 122 is installed.

The temperature sensor 122 is connected to the terminal Tm1 of themicrocomputer 110 via a wiring part 130. The wiring part 130 has one endconnected to the terminal Tm1 of the microcomputer 110 and the other endconnected to a terminal Tm2 of the temperature sensor 122.

In the example shown in FIG. 3 , the temperature sensor 122 includes athermistor 1222, a resistor 1223, and a capacitor 1224.

The thermistor 1222 is in the form of a variable resistor whoseresistance value changes according to temperature. The thermistor 1222may be, for example, a resistor whose resistance value changes in therange of 0.3 kΩ to 195 kΩ according to temperature. The thermistor 1222is connected in series with the resistor 1223, and is connected betweena power supply voltage 1221 (5 V in this example) and ground.

The resistor 1223 is in the form of a fixed resistor. The resistor 1223is connected in series with the thermistor 1222. The resistor 1223 isdisposed on the ground side. In a modification, the thermistor 1222 maybe disposed on the ground side, and the resistor 1223 may be disposed onthe power supply voltage 1221 side. A resistance value of the resistor1223 is fixed and may be, for example, about 5 kΩ.

The capacitor 1224 has one end connected to a connection point P1between the thermistor 1222 and the resistor 1223 and the other endconnected to ground. Charges corresponding to a potential of theconnection point P1 are accumulated in the capacitor 1224.

The connection point P1 between the thermistor 1222 and the resistor1223 is connected to the terminal Tm2 of the temperature sensor 122. Atthe connection point P1 between the thermistor 1222 and the resistor1223, a voltage is generated having a voltage value obtained by dividingthe power supply voltage 1221 (5 V in this example) by the resistancevalue of the thermistor 1222 and the resistance value of the resistor1223. Since this voltage value changes according to the resistance valueof the thermistor 1222, temperature information can be obtained based onthis voltage value.

FIG. 4 is an explanatory diagram of an output characteristic of thetemperature sensor 122, in which the horizontal axis represents actualtemperature, the vertical axis represents output (denoted as “A/Drecognition voltage” in FIG. 4 ) of the A/D converter 112, and a curveof the output characteristic of the temperature sensor 122 is shown.FIG. 5 is an explanatory diagram of disconnection in the wiring part130, in which a disconnection location is schematically indicated by thetext “disconnection” together with an X mark.

In the example shown in FIG. 4 , the output of the A/D converter 112corresponding to the output of the temperature sensor 122 increases asthe actual temperature increases. By utilizing such a characteristic,temperature information can be obtained based on the output of the A/Dconverter 112.

As schematically shown in FIG. 5 , in the configuration in which themicrocomputer 110 and the temperature sensor 122 are connected via thewiring part 130, disconnection may occur in the wiring part 130. Suchdisconnection causes the microcomputer 110 to be unable to obtainaccurate temperature information. When disconnection occurs in thewiring part 130, a voltage (input voltage of A/D converter 112) havingan indefinite value is generated in the terminal Tm1 of themicrocomputer 110.

Such a trouble occurs with respect to not only disconnection in thewiring part 130, but also disconnection in a wiring part 131 in theinput line 1121 in the microcomputer 110 between the terminal Tm1 and aconnection point P3, or disconnection in a wiring part 132 in thetemperature sensor 122 between the terminal Tm2 and a connection pointP4. The connection point P3 corresponds to a connection point with thepull-up circuit 113 in the input line 1121, and the connection point P4corresponds to a connection point with the capacitor 1224 in a signalline from the connection point P1 to the terminal Tm2. In the following,to simplify the description, the disconnection in the wiring part 130will be described as a representative. However, the same applies to thedisconnection in the wiring part 131 or the wiring part 132.

In the present embodiment, the microcomputer 110 detects disconnectionin the wiring part 130 by using the pull-up circuit 113 or the pull-downcircuit 114. Hereinafter, a method for detecting disconnection in thewiring part 130 is described in detail.

FIG. 6 and FIG. 7 are explanatory diagrams of a detection method usingthe pull-up circuit 113, and are explanatory diagrams of outputcharacteristics of the A/D converter 112 when the pull-up circuit 113 isturned on. The horizontal axis represents actual temperature, thevertical axis represents output (denoted as “A/D recognition voltage” inFIG. 6 and FIG. 7 ) of the A/D converter 112, and curves of the outputcharacteristics of the A/D converter 112 are shown. FIG. 6 shows anoutput characteristic 600 of the A/D converter 112 in a case where nodisconnection has occurred in the wiring part 130. FIG. 7 shows anoutput characteristic 630 of the A/D converter 112 in a case wheredisconnection has occurred in the wiring part 130. In FIG. 6 , acharacteristic 610 shown in FIG. 4 is shown by a dotted line forcomparison.

As shown in FIG. 6 , in the case where no disconnection has occurred inthe wiring part 130, the output of the A/D converter 112 is affected bythe output of the temperature sensor 122 and changes within a certainrange significantly greater than 0 V and significantly less than 5V.

In contrast, in the case where disconnection has occurred in the wiringpart 130, as shown in FIG. 7 , the output of the A/D converter 112sticks to a voltage value pulled up by the pull-up circuit 113 withoutbeing affected by the output of the temperature sensor 122. At thistime, the output of the A/D converter 112 is significantly higher than afirst predetermined threshold.

Accordingly, the following is known. Based on such a difference in theoutput of the A/D converter 112, that is, a difference occurring betweenthe case where no disconnection has occurred in the wiring part 130 andthe case where disconnection has occurred in the wiring part 130,disconnection in the wiring part 130 can be detected.

The same substantially applies in a case where the pull-down circuit 114is turned on instead of the pull-up circuit 113. In this case, in thestate in which disconnection has occurred in the wiring part 130, theoutput of the A/D converter 112 sticks to a voltage value pulled down bythe pull-down circuit 114. At this time, the output of the A/D converter112 is approximately 0 V. Accordingly, it is known that disconnection inthe wiring part 130 can be detected based on such a difference in theoutput of the A/D converter 112.

In this way, according to the present embodiment, disconnection in thewiring part 130 can be detected by using the pull-up circuit 113 or thepull-down circuit 114.

Next, details of functions of the processing part 111 of themicrocomputer 110 will be described with reference to FIG. 8 andsubsequent figures, while referring again to FIGS. 2 and 6 . In thefollowing, described is an example of detecting disconnection in thewiring part 130 by using the pull-up circuit 113. However, the pull-downcircuit 114 may also be used, as described above. In the case of usingthe pull-up circuit 113, the pull-down circuit 114 is turned off; in thecase of using the pull-down circuit 114, the pull-up circuit 113 isturned off. In a modification, both the pull-up circuit 113 and thepull-down circuit 114 may be used in a time-division manner.

As shown in FIG. 2 , the microcomputer 110 includes a switch controlpart 200, a sensor information generator 210, a disconnection detector220, and a sensor failure detector 230. The switch control part 200, thesensor information generator 210, the disconnection detector 220, andthe sensor failure detector 230 can be realized by the CPU of theprocessing part 111 executing a program in the storage.

The switch control part 200 controls on/off states of the switchingelement SW1 of the pull-up circuit 113. In the present embodiment, theswitch control part 200 turns on the switching element SW1 while apredetermined condition is satisfied. In this case, the switch controlpart 200 turns on the switching element SW1 when the predeterminedcondition is satisfied, and turns off the switching element SW1 when thepredetermined condition is no longer satisfied.

Here, as shown in FIG. 6 , the output characteristic 600 of the A/Dconverter 112 when the pull-up circuit 113 is on is different from theoutput characteristic 610 of the A/D converter 112 when the pull-upcircuit 113 is off. Accordingly, in a configuration of generatingtemperature information based on a calculation formula adapted to theoutput characteristic 610, if the temperature information is generatedbased on the output characteristic 600, accurate temperature informationcannot be obtained. That is, in the case of generating temperatureinformation based on the output characteristic 600 by using thecalculation formula adapted to the output characteristic 610, due to theinfluence of fluctuations that may be caused by the pull-up circuit 113,accurate temperature information cannot be obtained. To newly adapt thecalculation formula based on the output characteristic 600, a complexcalculation formula such as a high-order function is obtained, which isdisadvantageous from the viewpoint of calculation load.

In view of this, the predetermined condition is preferably adapted so asto be satisfied only during a period during which acquisition oftemperature information is unnecessary or a period during whichacquisition of highly accurate temperature information is unnecessary.For example, the predetermined condition may be satisfied in relation toinitialization or sleep mode. Specifically, the predetermined conditionis satisfied over a part of or the whole of an initialization period ofthe microcomputer 110, and/or is satisfied over a part of or the wholeof a sleep mode period of the microcomputer 110. Accordingly, thepull-up circuit 113 can be turned on under an appropriate condition thatacquisition of temperature information or the like is unnecessary.

The sensor information generator 210 generates temperature informationas sensor information based on a sensor signal from the temperaturesensor 122. In the present embodiment, as described above, if thetemperature information is generated based on the output of the A/Dconverter 112 when the pull-up circuit 113 is on by using thecalculation formula adapted to the output characteristic 610, accuratetemperature information cannot be obtained. Accordingly, the sensorinformation generator 210 generates the temperature information based onthe sensor signal from the temperature sensor 122 when the pull-upcircuit 113 is off by the calculation formula adapted to the outputcharacteristic 610. Accordingly, while disconnection in the wiring part130 is able to be detected by using the pull-up circuit 113, a trouble(decrease in accuracy of temperature information) caused by the pull-upcircuit 113 can be prevented.

The disconnection detector 220 detects disconnection of the wiring part130 based on the output of the A/D converter 112 when the pull-upcircuit 113 is on. A method for detecting disconnection of the wiringpart 130 is as described above with reference to FIG. 6 . Specifically,the disconnection detector 220 detects disconnection of the wiring part130 in the case where the output of the A/D converter 112 when thepull-up circuit 113 is on exceeds the first predetermined threshold. Thefirst predetermined threshold may be set greater than an upper limit ofa range that the output of the A/D converter 112 when the pull-upcircuit 113 is on may take when no disconnection has occurred in thewiring part 130. For example, in the example shown in FIG. 6 , theoutput characteristic 600 changes in a range having an upper limitsignificantly lower than 4.9 V. Accordingly, in this case, the firstpredetermined threshold may be set to 4.9 V.

In a configuration using the pull-down circuit 114, the disconnectiondetector 220 detects disconnection of the wiring part 130 in the casewhere the output of the A/D converter 112 when the pull-down circuit 114is on falls below the second predetermined threshold. The secondpredetermined threshold may be set less than a lower limit of a rangethat the output of the A/D converter 112 when the pull-down circuit 114is on may take when no disconnection has occurred in the wiring part130. For example, the second predetermined threshold may be set to avalue (for example, about 0.025 V) slightly greater than 0.

In the case where the disconnection detector 220 detects disconnectionof the wiring part 130, the disconnection detector 220 may generateinformation (for example, diagnostic information) indicating the same.In this case, the host ECU 4 may generate an output instruction such asan alarm based on such information.

The sensor failure detector 230 detects various failures of thetemperature sensor 122 based on the output of the A/D converter 112 whenthe pull-up circuit 113 is in the off state. Accordingly, the sensorfailure detector 230 operates together with the sensor informationgenerator 210 based on the output of the A/D converter 112 when thepull-up circuit 113 is in the off state.

Specifically, the sensor failure detector 230 detects a power fault inthe temperature sensor 122 in the case where the output of the A/Dconverter 112 when the pull-up circuit 113 is in the off state exceeds athird predetermined threshold. At the time of the power fault of thetemperature sensor 122, the output of the A/D converter 112 sticks to avalue corresponding to the power supply voltage 1221, similarly to theoutput characteristic 630 of the A/D converter 112 (see FIG. 7 ) in thecase where disconnection has occurred in the wiring part 130.Accordingly, in this case, the power fault of the temperature sensor 122can be detected by the third predetermined threshold that is the same asthe first predetermined threshold used for disconnection detection bythe disconnection detector 220. That is, the third predeterminedthreshold may be the same as the first predetermined threshold used fordisconnection detection by the disconnection detector 220.

A ground fault in the temperature sensor 122 is detected in the casewhere the output of the A/D converter 112 when the pull-up circuit 113is in the off state falls below a fourth predetermined threshold. Theground fault of the temperature sensor 122 is caused by, for example,disconnection in a signal line from the power supply voltage 1221(denoted in FIG. 3 ) to the connection point P1, as schematically shownin FIG. 8 . Also in this case, since the power supply voltage 1221 isseparated from the terminal Tm2 of the temperature sensor 122, theterminal Tm2 of the temperature sensor 122 has ground potential. Hence,when the temperature sensor 122 has a ground fault, the output of theA/D converter 112 sticks to 0 V. Accordingly, in this case, the groundfault of the temperature sensor 122 can be detected by the fourthpredetermined threshold that is the same as the second predeterminedthreshold used for disconnection detection by the disconnection detector220. That is, the fourth predetermined threshold may be the same as thesecond predetermined threshold when disconnection detection is performedusing the pull-down circuit 114.

In the case where the sensor failure detector 230 detects a power faultor a ground fault in the temperature sensor 122, the sensor failuredetector 230 may generate failure information (for example, diagnosticinformation) indicating the same. In this case, the host ECU 4 maygenerate an output instruction such as an alarm based on suchinformation. The failure information may include information indicatingthe type (power fault or ground fault) of failure.

Next, an operation example of the microcomputer 110 related todisconnection detection or the like is described with reference to FIG.9 to FIG. 12 .

FIG. 9 is a timing chart in a case where disconnection detectionprocessing by the disconnection detector 220 is performed duringinitialization processing of the microcomputer 110. In FIG. 9 , a timeseries waveform of the power supply voltage Vcc, a time series of thecontent of software processing, and a time series of the on/off state ofthe pull-up circuit 113 are shown in order from the upper side. FIG. 10and FIG. 11 are timing charts of a failure determination method by thesensor failure detector 230. In each of FIG. 10 and FIG. 11 , a timeseries of the output (denoted as “sensor output” in FIG. 10 and FIG. 11) of the temperature sensor 122 corresponding to the output of the A/Dconverter 112, and a time series of a sensor failure determinationresult are shown in order from the top.

In the example shown in FIG. 9 , for example, when the power supplyvoltage Vcc rises at time point t0 as the vehicle is started,initialization processing of the microcomputer 110 is executed during aperiod from time point t0 to time point t1. The disconnection detectionprocessing by the disconnection detector 220 is executed using theperiod from time point t0 to time point t1. Specifically, the pull-upcircuit 113 is on during the period from time point t0 to time point t1,and based on the output of the A/D converter 112 when the pull-upcircuit 113 is in the on state, the disconnection detection processingby the disconnection detector 220 is executed.

When the initialization processing of the microcomputer 110 iscompleted, the pull-up circuit 113 is turned off at time point t1, andstationary processing is executed. At this time, the sensor informationgenerator 210 and the sensor failure detector 230 function, and sensormeasurement (generation of temperature information) and failuredetermination of the temperature sensor 122 are executed. In this case,the failure determination of the temperature sensor 122 is realized, forexample, in the manner shown in FIG. 10 and FIG. 11 . In each of FIG. 10and FIG. 11 , a power fault and a ground fault occur at time points t4and t5, respectively. Specifically, in the example shown in FIG. 10 , apower fault occurs at time point t4, and the output of the temperaturesensor 122 corresponding to the output of the A/D converter 112 sticksto a value (value higher than the third predetermined threshold) higherthan an upper limit in a normal mode. In this case, due to detection ofthe power fault at a failure determination timing t6, the sensor failuredetermination result changes from “normal” to “abnormal”. In the exampleshown in FIG. 11 , a ground fault occurs at time point t5, and theoutput of the temperature sensor 122 corresponding to the output of theA/D converter 112 sticks to a value (value lower than the fourthpredetermined threshold) lower than a lower limit in the normal mode. Inthis case, due to detection of the ground fault at a failuredetermination timing t7, the sensor failure determination result changesfrom “normal” to “abnormal”.

In the example shown in FIG. 9 , the pull-up circuit 113 is in the onstate throughout the whole period of the initialization processing ofthe microcomputer 110. However, the pull-up circuit 113 may be turned ononly during a period during which the disconnection detection processingby the disconnection detector 220 is executed in the whole period of theinitialization processing.

FIG. 12 is a timing chart in a case where the disconnection detectionprocessing by the disconnection detector 220 is performed in the sleepmode of the microcomputer 110. In FIG. 12 , similarly to FIG. 9 , a timeseries waveform of the power supply voltage Vcc, a time series of thecontent of software processing, and a time series of the on/off state ofthe pull-up circuit 113 are shown in order from the upper side.

In the example shown in FIG. 12 , the microcomputer 110 transitions tothe sleep mode during a period from time point t2 to time point t3. Thedisconnection detection processing by the disconnection detector 220 isexecuted using the period from time point t2 to time point t3.Specifically, the pull-up circuit 113 is on during the period from timepoint t2 to time point t3, and based on the output of the A/D converter112 when the pull-up circuit 113 is in the on state, the disconnectiondetection processing by the disconnection detector 220 is executed. Whenthe sleep mode of the microcomputer 110 ends, the pull-up circuit 113 isturned off at time point t3, and stationary processing is executed. Atthis time, the sensor information generator 210 and the sensor failuredetector 230 function, and sensor measurement (generation of temperatureinformation) and failure determination of the temperature sensor 122 areexecuted.

In the example shown in FIG. 12 , the pull-up circuit 113 is in the onstate throughout the whole period of the sleep mode of the microcomputer110. However, the pull-up circuit 113 may be turned on only during aperiod during which the disconnection detection processing by thedisconnection detector 220 is executed in the whole period of the sleepmode. It is not always necessary to execute the disconnection detectionprocessing for each sleep mode, and the disconnection detectionprocessing may be executed in the sleep mode after a predeterminedperiod of time or more has elapsed from the previous disconnectiondetection processing.

Although the embodiments of the disclosure have been described in detailwith reference to the drawings, the specific configuration is notlimited thereto, and designs and the like within the scope not deviatingfrom the gist of the disclosure are also included.

For example, in the embodiments described above, the temperature sensor122 is a sensor that inputs an analog sensor signal to the microcomputer110. However, such a sensor may be one other than the temperature sensor122. For example, the sensor that inputs an analog sensor signal to themicrocomputer 110 may be a current sensor, a voltage sensor, a rotationangle sensor, or the like.

Regarding the above embodiments, the following supplementary notes arefurther disclosed.

[Supplementary Note 1]

A control system (for example, motor drive system 2 or motor controldevice 10) including: a semiconductor chip (for example, microcomputer110), having built therein a processing part (111), an A/D converter(112) and a pull device circuit (113, 114); a wiring part (130, 131,132), having one end connected to a terminal connected to the A/Dconverter; and a sensor (for example, temperature sensor 122), connectedto the other end of the wiring part and inputting a sensor signal inanalog form to the terminal via the wiring part, in which the pulldevice circuit includes a switching element (SW1, SW2), and has one endconnected to ground or a power supply voltage and the other endconnected between the A/D converter and the terminal; the processingpart includes: a switch control part (200), controlling the switchingelement to be in an on or off state; a sensor information generator(210), generating sensor information based on the sensor signal; and adisconnection detector (220), detecting disconnection of the wiring partbased on output of the A/D converter when the switching element is inthe on state.

According to the configuration of supplementary note 1, the followingcontrol system can be obtained. In the configuration in which the sensorsignal in analog form is input to the terminal of the semiconductor chipvia the wiring part, it is possible to detect disconnection of thewiring part without adding a new component (by using the pull devicecircuit built in the semiconductor chip).

[Supplementary Note 2]

The control system as described in supplementary note 1, in which thesensor information generator generates the sensor information based onthe output of the A/D converter when the switching element is in the offstate.

According to the configuration of supplementary note 2, highly accuratesensor information can be obtained in a mode not affected by the pulldevice circuit.

[Supplementary Note 3]

The control system as described in supplementary note 1 or 2, in whichthe switch control part turns on the switching element while apredetermined condition is satisfied.

According to the configuration of supplementary note 3, a period duringwhich the pull device circuit and the accompanying disconnectiondetector function can be appropriately limited.

[Supplementary Note 4]

The control system as described in supplementary note 3, in which thepredetermined condition is satisfied in relation to initialization orsleep mode.

According to the configuration of supplementary note 4, the pull devicecircuit and the accompanying disconnection detector are able to functionin relation to the initialization or the sleep mode being a timing atwhich it is less necessary to obtain the sensor information.

[Supplementary Note 5]

The control system as described in any one of supplementary notes 1 to4, in which the disconnection detector detects the disconnection of thewiring part in response to the output of the A/D converter when theswitching element is in the on state exceeding a first predeterminedthreshold or falling below a second predetermined threshold.

According to the configuration of supplementary note 5, disconnection ofthe wiring part can be accurately detected based on a relationshipbetween the output of the A/D converter and a predetermined threshold.

[Supplementary Note 6]

The control system as described in supplementary note 5, in which theprocessing part further includes a sensor failure detector (230); thesensor failure detector detects a power fault in the sensor in responseto the output of the A/D converter when the switching element is in theoff state exceeding a third predetermined threshold, and the sensorfailure detector detects a ground fault in the sensor in response to theoutput of the A/D converter when the switching element is in the offstate falling below a fourth predetermined threshold.

According to the configuration of supplementary note 6, not onlydisconnection of the wiring part but also a power fault or a groundfault in the sensor can be detected. Since a power fault or a groundfault in the sensor can be detected based on the output used whenobtaining the sensor information, the failure can be quickly detectedwhen it occurs.

[Supplementary Note 7]

A disconnection detection method in a control system, the control systemincluding: a semiconductor chip, having built therein a processing part,an A/D converter and a pull device circuit; a wiring part, having oneend connected to a terminal connected to the A/D converter; and asensor, connected to the other end of the wiring part and inputting asensor signal in analog form via the wiring part, in which the pulldevice circuit includes a switching element, and has one end connectedto ground or a power supply voltage and the other end connected betweenthe A/D converter and the terminal, the disconnection detection methodincludes: controlling the switching element to be in an on or off stateby the processing part; generating sensor information based on thesensor signal by the processing part; and detecting disconnection of thewiring part based on output of the A/D converter when the switchingelement is in the on state.

According to the configuration of supplementary note 7, the followingdisconnection detection method can be obtained. In the control system inwhich the sensor signal in analog form is input to the terminal of thesemiconductor chip via the wiring part, it is possible to detectdisconnection of the wiring part without adding a new component (byusing the pull device circuit built in the semiconductor chip).

[Supplementary Note 8]

A disconnection detection program in a control system, the controlsystem including: a semiconductor chip, having built therein aprocessing part, an A/D converter and a pull device circuit; a wiringpart, having one end connected to a terminal connected to the A/Dconverter; and a sensor, connected to the other end of the wiring partand inputting a sensor signal in analog form via the wiring part, inwhich the pull device circuit includes a switching element, and has oneend connected to ground or a power supply voltage and the other endconnected between the A/D converter and the terminal, the disconnectiondetection program causes the processing part to execute: processing forcontrolling the switching element to be in an on or off state;processing for generating sensor information based on the sensor signal;and processing for detecting disconnection of the wiring part based onoutput of the A/D converter when the switching element is in the onstate.

According to the configuration of supplementary note 8, the followingdisconnection detection program can be obtained. In the control systemin which the sensor signal in analog form is input to the terminal ofthe semiconductor chip via the wiring part, it is possible to detectdisconnection of the wiring part without adding a new component (byusing the pull device circuit built in the semiconductor chip).

What is claimed is:
 1. A control system comprising: a semiconductorchip, having built therein a processing part, an A/D converter and apull device circuit; a wiring part, having one end connected to aterminal connected to the A/D converter; and a sensor, connected to theother end of the wiring part and inputting a sensor signal in analogform to the terminal via the wiring part, wherein the pull devicecircuit comprises a switching element, and has one end connected toground or a power supply voltage and the other end connected between theA/D converter and the terminal; the processing part comprises: a switchcontrol part, controlling the switching element to be in an on or offstate; a sensor information generator, generating sensor informationbased on the sensor signal; and a disconnection detector, detectingdisconnection of the wiring part based on output of the A/D converterwhen the switching element is in the on state, wherein the disconnectiondetector detects the disconnection of the wiring part in response to theoutput of the A/D converter when the switching element is in the onstate exceeding a first predetermined threshold or falling below asecond predetermined threshold, wherein the processing part furthercomprises a sensor failure detector, and the sensor failure detectordetects a power fault in the sensor in response to the output of the A/Dconverter when the switching element is in the off state exceeding athird predetermined threshold, and the sensor failure detector detects aground fault in the sensor in response to the output of the A/Dconverter when the switching element is in the off state falling below afourth predetermined threshold.
 2. The control system according to claim1, wherein the sensor information generator generates the sensorinformation based on the output of the A/D converter when the switchingelement is in the off state.
 3. The control system according to claim 1,wherein the switch control part turns on the switching element while apredetermined condition is satisfied.
 4. The control system according toclaim 3, wherein the predetermined condition is satisfied in relation toinitialization or sleep mode.
 5. A disconnection detection method in acontrol system, the control system comprising: a semiconductor chip,having built therein a processing part, an A/D converter and a pulldevice circuit; a wiring part, having one end connected to a terminalconnected to the A/D converter; and a sensor, connected to the other endof the wiring part and inputting a sensor signal in analog form to theterminal via the wiring part, wherein the pull device circuit comprisesa switching element, and has one end connected to ground or a powersupply voltage and the other end connected between the A/D converter andthe terminal, wherein the disconnection detection method comprises:controlling the switching element to be in an on or off state by theprocessing part; generating sensor information based on the sensorsignal by the processing part; detecting, by the processing part,disconnection of the wiring part based on output of the A/D converterwhen the switching element is in the on state, wherein the disconnectionof the wiring part is detected in response to the output of the A/Dconverter when the switching element is in the on state exceeding afirst predetermined threshold or falling below a second predeterminedthreshold; and detecting, by the processing part, a power fault in thesensor in response to the output of the A/D converter when the switchingelement is in the off state exceeding a third predetermined threshold,and a ground fault in the sensor in response to the output of the A/Dconverter when the switching element is in the off state falling below afourth predetermined threshold.
 6. A non-transitory computer-readablemedium storing a disconnection detection program in a control system,the control system comprising: a semiconductor chip, having builttherein a processing part, an A/D converter and a pull device circuit; awiring part, having one end connected to a terminal connected to the A/Dconverter; and a sensor, connected to the other end of the wiring partand inputting a sensor signal in analog form to the terminal via thewiring part, wherein the pull device circuit comprises a switchingelement, and has one end connected to ground or a power supply voltageand the other end connected between the A/D converter and the terminal,wherein the disconnection detection program causes the processing partto execute: processing for controlling the switching element to be in anon or off state; processing for generating sensor information based onthe sensor signal; processing for detecting disconnection of the wiringpart based on output of the A/D converter when the switching element isin the on state, wherein the disconnection of the wiring part isdetected in response to the output of the A/D converter when theswitching element is in the on state exceeding a first predeterminedthreshold or falling below a second predetermined threshold; andprocessing for detecting a power fault in the sensor in response to theoutput of the A/D converter when the switching element is in the offstate exceeding a third predetermined threshold, and detecting a groundfault in the sensor in response to the output of the A/D converter whenthe switching element is in the off state falling below a fourthpredetermined threshold.
 7. The control system according to claim 2,wherein the switch control part turns on the switching element while apredetermined condition is satisfied.